Monte Carlo Study of Doping Change and Disorder Effect on Double Exchange Ferromagnetism

TL;DR

This study uses Monte Carlo simulations to analyze how doping and disorder influence the phase diagram, critical properties, and ferromagnetic transition in a three-dimensional double exchange model, providing insights relevant to manganites.

Contribution

It systematically investigates the effects of doping and quenched disorder on the critical behavior and Curie temperature in the double exchange model using Monte Carlo methods.

Findings

Curie temperature scales with the electrons' kinetic energy

Transition belongs to the short-range Heisenberg universality class

Results align with experimental data in colossal magnetoresistance manganites

Abstract

Phase diagram and critical properties are studied for three-dimensional double exchange model with and without quenched disorder. Employing the Monte Carlo method and the systematic analysis on the finite-size effect, we estimate the Curie temperature and the critical exponent as functions of the doping concentration and the strength of the random potential. The Curie temperature well scales to the kinetic energy of electrons in the ground state as expected for this kinetics-driven ferromagnetism. The universality class of this transition is described by the short-range Heisenberg fixed point. The results are compared with the experimental results in the colossal magnetoresistance manganites.